Hannah Arendt's spatial thinking: an introduction. Territory, Politics, Governance. Hannah Arendt is not among the philosophers most quoted by geographers and social scientists interested in the spatial dimension of social life; and when she is, authors typically cite one or two examples or concepts of her work, while neglecting to place her related propositions in the context of the various ways she refers to spatiality or territoriality. This paper aims to give a broad overview of her spatial thinking. More precisely, it presents the various spatial concepts Arendt uses (place, space, territory, world, location, etc.), and suggests that a tri-partite spatial ontology is at work behind her lexicon. Since such an ontological trilogy is never explicit in Arendt's work, it is compared to the architecture of Arendt's explicit theorization which is structured around different sets of concepts (identity/plurality; labour/work/action). Then, the paper explains that an ontological analysis of Arendt's proposals allows us to understand the major issues or tragedies that she focused on as being related to tensions between different forms of spatiality. I conclude that Arendt's extensive contributions in diverse conceptual and empirical fields are intrinsically spatially grounded.